Apparatus

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sensors Mode-S transponder

A75103

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N57016 · BOEING 777-200 · operated by UNITED AIRLINES INC

Hex
A75103
Octal
51650403
Decimal
10,965,251
Country
US
Tail
N57016
Type
B772
No current signal · last broadcast Jul 26, 21:55 UTC
Flights observed
252
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:55 UTC

Last known position

Most recent position reported by Mode-S A75103.

Country allocation

The ICAO 24-bit address A75103 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
UAL933 - 13 2026-07-05
UAL927 - 13 2026-07-09
UAL876 - 11 2026-06-30
UAL926 - 9 2026-07-09
UAL506 - 8 2026-07-13
UAL131 - 8 2026-06-29
UAL932 - 7 2026-06-20
UAL889 - 7 2026-07-12
UAL888 - 7 2026-07-11
UAL875 - 7 2026-06-13
UAL917 - 5 2026-07-10
UAL916 - 5 2026-07-11
UAL901 United Airlines 5 2026-04-24
UAL900 United Airlines 5 2026-04-17
UAL853 United Airlines 5 2026-07-24
UAL672 United Airlines 5 2026-07-26
UAL45 United Airlines 5 2026-06-23
UAL44 United Airlines 5 2026-06-22
UAL23 United Airlines 5 2026-07-23
UAL130 United Airlines 5 2026-05-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL673 SFO → BOS Jul 26, 14:40 UTCJul 26, 21:55 UTC7h 15m
2026-07-26 UAL672 EWR → ATL Jul 26, 01:29 UTCJul 26, 11:48 UTC10h 19m
2026-07-26 UAL672 EWR → ATL Jul 26, 01:35 UTCJul 26, 11:55 UTC10h 21m
2026-07-25 UAL852 TPE → SAN Jul 25, 11:15 UTCJul 25, 20:55 UTC9h 40m
2026-07-25 UAL852 TPE → SAN Jul 25, 09:25 UTCJul 25, 09:40 UTC15m
2026-07-24 UAL853 SFO → TPE Jul 24, 19:25 UTCJul 24, 19:50 UTC25m
2026-07-24 UAL853 SFO → TPE Jul 24, 07:41 UTCJul 24, 19:40 UTC11h 59m
2026-07-24 UAL853 SFO → TPE Jul 24, 07:45 UTCJul 24, 18:10 UTC10h 25m
2026-07-23 UAL2328 ORD → SFO Jul 23, 20:00 UTCJul 24, 01:20 UTC5h 20m
2026-07-23 UAL22 DUB → EWR Jul 23, 08:50 UTCJul 23, 15:35 UTC6h 45m
2026-07-23 UAL23 EWR → DUB Jul 23, 06:00 UTCJul 23, 06:05 UTC5m
2026-07-23 UAL23 EWR → DUB Jul 23, 00:05 UTCJul 23, 06:05 UTC6h 0m
2026-07-23 UAL23 EWR → DUB Jul 23, 00:15 UTCJul 23, 05:45 UTC5h 30m
2026-07-22 UAL121 BCN → EWR Jul 22, 11:20 UTCJul 22, 18:30 UTC7h 10m
2026-07-21 UAL120 EWR → BCN Jul 21, 23:45 UTCJul 22, 06:55 UTC7h 10m
2026-07-21 UAL120 EWR → BCN Jul 21, 23:45 UTCJul 22, 00:55 UTC1h 10m
2026-07-21 UAL905 LHR → EWR Jul 21, 09:15 UTCJul 21, 16:15 UTC7h 0m
2026-07-21 UAL14 EWR → LHR Jul 21, 00:10 UTCJul 21, 06:35 UTC6h 25m
2026-07-20 UAL56 CDG → EWR Jul 20, 08:35 UTCJul 20, 15:55 UTC7h 20m
2026-07-19 UAL915 IAD → CDG Jul 19, 23:15 UTCJul 20, 06:25 UTC7h 10m
2026-07-18 UAL885 - Jul 18, 08:40 UTCJul 18, 17:50 UTC9h 10m
2026-07-17 UAL884 IAD → FCO Jul 17, 22:18 UTCJul 18, 06:16 UTC7h 58m
2026-07-17 UAL884 IAD → FCO Jul 17, 22:20 UTCJul 18, 06:15 UTC7h 56m
2026-07-17 UAL919 LHR → IAD Jul 17, 11:40 UTCJul 17, 19:19 UTC7h 39m
2026-07-17 UAL919 - Jul 17, 12:00 UTCJul 17, 12:45 UTC45m
2026-07-16 UAL880 - Jul 16, 21:50 UTCJul 17, 06:45 UTC8h 55m
2026-07-16 UAL879 - Jul 16, 09:40 UTCJul 16, 18:59 UTC9h 20m
2026-07-15 UAL918 IAD → LHR Jul 15, 23:30 UTCJul 16, 06:20 UTC6h 50m
2026-07-15 UAL914 - Jul 15, 11:05 UTCJul 15, 19:05 UTC8h 0m
2026-07-14 UAL990 SFO → CDG Jul 14, 22:40 UTCJul 15, 09:00 UTC10h 19m
2026-07-13 UAL506 - Jul 13, 14:35 UTCJul 13, 17:15 UTC2h 40m
2026-07-13 UAL506 FCO → SFO Jul 13, 14:07 UTCJul 14, 02:43 UTC12h 36m
2026-07-13 UAL507 - Jul 13, 00:25 UTCJul 13, 11:25 UTC11h 0m
2026-07-12 UAL889 - Jul 12, 10:40 UTCJul 12, 12:40 UTC2h 0m
2026-07-12 UAL889 PEK → SFO Jul 12, 09:51 UTCJul 12, 20:56 UTC11h 5m
2026-07-11 UAL888 - Jul 11, 18:15 UTCJul 12, 05:50 UTC11h 35m
2026-07-11 UAL916 - Jul 11, 02:05 UTCJul 11, 13:30 UTC11h 25m
2026-07-10 UAL917 SFO → AKL Jul 10, 06:46 UTCJul 10, 19:11 UTC12h 25m
2026-07-10 UAL917 - Jul 10, 06:50 UTCJul 10, 07:20 UTC30m
2026-07-09 UAL927 - Jul 9, 16:10 UTCJul 9, 18:45 UTC2h 35m
2026-07-09 UAL927 FRA → SFO Jul 9, 15:51 UTCJul 10, 02:58 UTC11h 7m
2026-07-09 UAL927 FRA → SFO Jul 9, 15:51 UTCJul 10, 03:03 UTC11h 12m
2026-07-09 UAL926 SFO → FRA Jul 9, 03:35 UTCJul 9, 13:45 UTC10h 10m
2026-07-08 UAL195 - Jul 8, 14:00 UTCJul 9, 01:20 UTC11h 20m
2026-07-08 UAL102 - Jul 8, 02:05 UTCJul 8, 11:55 UTC9h 50m
2026-07-08 UAL102 IAH → MUC Jul 8, 00:52 UTCJul 8, 11:53 UTC11h 1m
2026-07-06 UAL4 - Jul 6, 15:15 UTCJul 7, 00:40 UTC9h 25m
2026-07-06 UAL924 IAD → LHR Jul 6, 04:55 UTCJul 6, 11:25 UTC6h 30m
2026-07-05 UAL933 FRA → IAD Jul 5, 16:15 UTCJul 6, 01:10 UTC8h 55m
2026-07-05 UAL933 FRA → IAD Jul 5, 15:46 UTCJul 6, 01:10 UTC9h 24m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the N57016 page for operator, model, and routing details .

Mode-S A75103 frequently asked

What is Mode-S code A75103?
A75103 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N57016.
Where is Mode-S A75103 registered?
Mode-S code A75103 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A75103 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:55 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A75103, octal 51650403, decimal 10,965,251.
What flights does A75103 operate?
Mode-S A75103 has broadcast 20 distinct callsigns, including UAL933, UAL927, UAL876, UAL926, UAL506.